Semiconductor component manufacturers are constantly striving to increase the speed of their components. Because a semiconductor component, such as a microprocessor, contains up to a billion transistors or devices, the focus for increasing speed has been to decrease gate delays of the semiconductor devices that make up the semiconductor component. As a result, the gate delays have been decreased to the point that speed is now primarily limited by the propagation delay of the metallization system used to interconnect the semiconductor devices with each other and with elements external to the semiconductor component. Metallization systems are typically comprised of a plurality of interconnect layers vertically separated from each other by a dielectric material and electrically coupled to each other by metal-filled vias or conductive plugs. Each layer contains metal lines, metal-filled vias, or combinations thereof separated by an insulating material. A figure of merit describing the delay of the metallization system is the Resistor-Capacitance (RC) delay. The RC delay can be derived from the resistance of the metal layer and the associated capacitance within and between different layers of metal in the metallization system.
The RC delay can be reduced by lowering either the capacitance of the metallization system, the resistance of the metallization system, or both. The capacitance can be lowered by decreasing the dielectric constant of the dielectric material and/or increasing the thickness of the dielectric material. The resistance of the metallization system can be lowered by decreasing the resistivity of the metallic interconnect layers, decreasing the resistivity of the conductive plugs that electrically couple the interconnect layers to each other, decreasing the length of the metallic interconnect, or increasing the thickness of the metal. Increasingly, semiconductor manufacturers are switching to metallization systems comprising copper because of its low resistivity and dielectric material having a low dielectric constant, i.e., low κ dielectrics. A drawback of this type of metallization system is that as the current density is increased, copper extrusion occurs which shorts adjacent conductor lines thereby causing the semiconductor component to fail. Detection of these types of shorts can be very difficult because of the number of metallization layers in high performance semiconductor components and their complex routing structure.
Accordingly, what is needed is a semiconductor component having an extrusion monitoring structure and a method for manufacturing the semiconductor component and monitoring the integrity of the metallization system.